1. August 31st 1997, aged 12: the death of Princess Diana

Marv woke me up that morning, giggling in that way that mostly meant he was playing a prank. Or something major had happened. "The princess is dead!" he warbled. Sure, Marv, sure. Let's check with Ma... oh.

The shock was tangible for days. Regular television went out of the window. My parents were glued to the news coverage. How could something like this happen to such a loving person? How could the media be allowed to get away with it?

The impact was a little lost on my nearly-thirteen-year-old self at the time, but it changed two things indefinitely: the public regard of the media and its methods, and the mythological British "stiff upper lip" - gone forever.

2. September 11th 2001, seventeen days before my 17th birthday

I asked Ma if she could lend me bus fare so I could get to my after-school job. She hated me working there, and we argued about it. Afterwards, she told me that a plane had hit the World Trade Centre. I'd never heard of the place.

But the pictures I saw on the news that night made me sick to my stomach.

Oddly enough, in psychology class the next day, we were scheduled to discuss something called "flashbulb memory" - something so shocking and important that you remember exactly where you were and what you were doing when you heard about it. No better example.

The trouble with 9/11 was that, awful as it was, it gave others free rein to do more awful things in its wake. An illegal war, the removal of civil liberties, and more and more death.

3. July 6th and 7th 2005, aged 20: a tale of two Londons

I watched the news at Matt's house with baited breath as London was named the host city for the 2012 Olympics. What an achievement, what an honour! That day we seemed invincible.

How wrong we were proven, the very next day.

To my mind, the attacks were planned exactly to take advantage of the city's mood that day. London thought herself to be all-powerful, far beyond that shadowy word "terrorism". Terrorism was something that happened to other people.

I remember calling my then-best friend on the 6th, to cheer about the Olympics. She didn't care. I also remember calling her the next day, in shock at the carnage. She still didn't care. I guess that was significant for me as an individual, in that it goes some way to explaining why I no longer count her as a friend. Strange how such huge catastrophes have such small reverberations.